Cancel MIDI permission request infobar on MIDIAccess stop.
On WebCore::MIDIAccess::stop(), renderer didn't cancel the MIDI
permission request infobar. As a result, when an iframe webpage that
requested MIDI permission is navigated away, the MIDI infobar is not
dismissed, unlike the geolocation infobar. This CL makes the MIDI infobar
be dismissed on WebCore::MIDIAccess::stop().
BUG=309893
Review URL: https://codereview.chromium.org/
38043004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231719 0039d316-1c4b-4281-b951-d872f2087c98